U.S. Pat. Nos. 3,310,901 and 4,145,828 disclose spring-biased front loading picture and poster frames. The frames have a plurality of frame sections, each frame section having a base member attached to a backing member and a rotatable cover member attached to each of the base members. Spring biasing mechanisms, such as S-shaped springs or bowed flat springs are used to bias the cover member relative to the base member in its open and closed positions. One or more metal spring members are used to bias the cover members on each of the sides of the poster frame. The poster frames in accordance with the '901 and '828 patents work very well and have secured substantial success in the marketplace.
Known picture and poster frames made in accordance with the '901 and '828 patents are typically made from a plurality of frame sections mitered at 45.degree. in the corners. The members forming each of the frame sections are typically made from an extruded metal material, such as aluminum. Also, it is possible to provide frames made from frame sections of extruded plastic materials. With the plastic extrusions, the spring mechanism is extruded integrally with the base and cover members. Frames of this type are shown, for example, in U.S. Pat. Nos. 4,512,094 and 4,523,400.
When extruded metal materials, such as aluminum, are used for the base members and cover members in poster frames, experiences have shown that over time and frequent usage of the poster frame, the cover members can slide longitudinally or laterally relative to the base member. Such sliding can cause difficulties during opening and closing of the frame sections. In order to prevent such sliding movement, one or more threaded rod members or mechanisms can be utilized, such as shown, for example, in U.S. Pat. No. 4,958,458. The two frame members can also be notched or staked together to prevent relative lateral movement.
It is an object of the present invention to provide an improved picture and poster frame. It is another object of the present invention to provide a picture and poster frame with a spring mechanism which eliminates rail locks and other mechanisms typically utilized with metal extruded frame sections to hold them from sliding laterally relative to one another.
It is a further object of the present invention to provide a poster frame which is simpler and less expensive to manufacture and assemble than known picture and poster frames. It is a still further object of the present invention to provide a spring mechanism for a poster frame which creates a final product which is easier to manufacture and assemble and which is less expensive.